Sen. Marco Rubio showed a lighthearted side during CNBC's interview on Wednesday, responding to the social media firestorm surrounding a photo that allegedly showed him awkwardly greeting Ivanka Trump with a hug.

Rubio, who unsuccessfully challenged her father Donald Trump for the 2016 Republican presidential nomination, joked on "Squawk Box" that it "wasn't a hug," when asked about the purported embrace that apparently started with a tweet from an Associated Press correspondent.

Rubio said on CNBC with a smile, "That's been fully investigated. We looked at that deeply. It's important that people know senators are capable of carrying out a traditional greeting. And so, I stand by our investigation. He added, "It wasn't a hug. But that's fine. We stand by the investigation."

At the Florida senator's invitation, Ivanka Trump was on Capitol Hill Tuesday to talk about pro-family tax reform. Rubio, a member of the Senate Intelligence Committee, made light of it in a tweetstorm on Tuesday.